Cutoff mechanism for strip molding

ABSTRACT

Presented is an automatic cutoff machine for cutting to length strip material as it is discharged in a continuous length from an automatic machine. The cutoff mechanism includes sensing means adjustable to sense a predetermined length of strip and operable to activate a cutoff saw to cut the strip to the predetermined length. Because the strip being cut is moving, the cutoff mechanism must also move with the strip and at the same rate to preclude binding between the cutoff saw and the strip being cut.

United States Patent Craig et al.

[ CUTOFF MECHANISM FOR STRIP MOLDING Inventors: Fred A. Craig, San Jose;Allan M.

Hudson, Mountain View, both of Calif.

Thiokol Chemical Corporation, Bristol, Pa.

Filed: May 28, 1971 Appl. No.: 147,772

Assignee:

US. Cl. 83/289, 83/318, 83/490,

Int. Cl B26d 1/56 Field of Search 83/289, 293, 318,

References Cited UNITED STATES PATENTS 8/1940 Morris 83/319 X June 12,1973 2,757,734 8/1956 Richardson 83/320 X 2,019,465 10/1935 Rubin 83/289X 3,543,624 12/1970 Richards 83/289 X Primary Examiner-Francis S. HusarAttorney-Thomas W. Brennan [57] ABSTRACT 2 Claims, 8 Drawing Figures -47 I06 2 78 B3 2 Z 77 71 66 !76 73 e9 i 82 I 99 97 L 72 82 96 I03 L92 ll'a;

PAIENIED JUN 1 2 SHEET 2 Bf 6 INVENTOR FRED A. CRAIG BY ALLAN M. HUDSOZPAIENIED 1 2 SIEEHHIFS FARMER TRB-4 PHOTO CONTROL N C I62 SAFETY SWITCHTRB-3 HEAD SWITCH WARNER i) lO3-6 TRAVEL ll TRB RELAY CLUTCH WARNER *07- 9 HEAD N.O. u 7- 7 G? FRAME SWITCH TRB RELAY CLUTCH WARNER O l I 7- 8HEAD BRAKE N.O. I59 Il7- 7 HEAD SWITCH INVENTOR FRED A. CRAIG ALLAN M.HUDSON gm PAIENIEB JUN! Sim w 6 INVENTOR ALLAN M. HUDSON FRED A CRAIG WW CUTOFF MECHANISM FOR STRIP MOLDING BACKGROUND OF INVENTION In themanufacture of many different materials in continuous and elongatedrigid strips, such as molding, whether such strips be fabricated fromlumber in the conventional way, or fabricated from one of the manysynthetic resinous materials suitable for this purpose, the elongatedrigid strips must be cut of appropriate lengths for bundling andshipment to ultimate consumers or consumer outlets. In general, rigidstrip material is used for trimming around windows and doors and must,therefore, be cut to lengths that are appropriate for such use.Accordingly, it is one of the objects of the invention to provide acutoff mechanism adjustable to cut off predetermined lengths from acontinuously moving elongated strip of material.

One of the problems encountered in cutting a predetermined length from acontinuously moving strip involves making the cut in such manner thatthe movement of the strip is uninterrupted. Accordingly, it is anotherobject of the invention to provide a cutoff mechanism which effects itsout without interrupting the continuous movement of the strip being cut.

Another problem encountered in cutting a moving strip of rigid materialis the tendency of the cutoff blade to bind in the material being cut.It has been found that such binding tendencies are precluded when thecutoff device is arranged to move with the material being cut and at thesame rate therewith. Accordingly, it is a still further object of theinvention to provide a cutoff mechanism adjustable to travel over apredetermined length in synchronism with the material being cut so as topreclude any tendency of binding between the cutoff device and thematerial being cut.

In providing a cutoff mechanism that moves with the material being cut,another problem is recovery of the cutoff mechanism and repositioningfor the next operation. Accordingly, it is a still further object of theinvention to provide a cutoff mechanism which not only movessynchronously with the material to be cut over a predetermined interval,but is returned to its initial position so as to initiate the next cut.

Another problem involves the overall transverse dimension through whichthe cut must be made. For instance, if an elongated strip three feet inwidth is being cut transversely, the cutting element must traverse theentire three-foot width to effect a complete cutoff. If a singlecircular saw blade, for instance, is moved perpendicularly through thestrip being cut, it is obvious that the cutoff blade would have toexceed three feet in diameter. Since a rotating mass of such diameterwould be unwieldy and dangerous, and in addition would require massiveequipment for its control, thus increasing its expense, it isadvantageous that the cut through the continuously moving strip,regardless of its width, be effected progressively from one edge of thestrip to the other. However, where the strip is moving continuously,this poses a problem because the cut must be made rapidly and thecutting element must, of course, move with the strip being cut andsimultaneously move transversely therethrough. Accordingly, it is astill further object of the invention to provide a cutoff mechanism inthe nature of a rotating circular saw blade of relatively small diameteradapted to move transversely with respect to the direction of movementof the strip being cut so as to effectively traverse the material beingcut from one edge thereof to the other.

BRIEF SUMMARY OF INVENTION In terms of broad inclusion, the cutoffmechanism of the invention comprises a rigid main support frame orientedso that the elongated material to be cut passes longitudinallytherethrough along appropriate conveyor means. Mounted on the main frameis an auxiliary carriage also adapted to move longitudinally along themain support frame at a rate equal to the material to be cut. To effectcutting of the material, there is mounted on the auxiliary carriageframe for movement therewith in synchronism with the material to be cut,cutoff means mounted on the free end of a rotatable cantilever arm.Appropriate sensing and control means, actuated by movement of theproduct through the main frame and by movement of the auxiliary carriagein synchronism with the product being cut, effects energization of adrive mechanism for effecting rotation of the cantilever arm on whichthe cutoff means is mounted.

BRIEF DESCRIPTION OF DRAWING I FIG. 1 is a side elevational view of thecutoff mechanism, partly in vertical section, portions of the framebeing broken away to reduce its size.

FIG. 2 is an enlarged vertical cross-sectional view taken in the planeindicated by the line 22 in FIG. 1.

FIG. 3 is a side elevational view illustrating the transition betweenthe discharge end of the strip forming apparatus and the cutoffmechanism forming the subject matter of this invention, illustrating themeans to effect cooling of the product emanating from the strip formingapparatus.

FIG. 4. is a schematic view in perspective illustrating the mechanicaland functional relationships between the main frame auxiliary carriage,cutoff means and DESCRIPTION OF PREFERRED EMBODIMENT In terms of greaterdetail, the cutoff mechanism for strip material is described hereinafterin relation to its use for cutting off to specific lengths plastic stripmaterial produced continuously in strip form. It should be understood,however, that the cutoff mechanism may be used to cut to length anymaterial or product that is manufactured in elongated form.

Referring to FIG. 1, there is shown a main support frame designatedgenerally by the numeral 2, and including a motor support standardhaving vertical legs 3 formed from structural iron connected at theirupper ends by a cross beam 4 so as to form an inverted U- shapedstandard on which appropriate drive means may be suspended, as willhereinafter be explained. Spaced longitudinally from the motor supportstandard and standing substantially parallel thereto is an auxiliarycarriage standard including vertical legs 6 connected at their upperends by a cross beam 7, the upstanding legs 6 and beam 7 forming aninverted U- shaped standard cooperating with a similarly configured butlower discharge end standard having vertically upstanding legs 8connected by a cross beam 9.

Rigidity as between the plurality of axially spaced standards isprovided by appropriately interposed structural elements such as tieplate 12 (FIG. 1) extending between cross beams 4 and 7 adjacent theupper ends of these standards, and longitudinally extending stringers 13and 14 (FIGS. 1 and 7) spaced intermediate the ends of legs 3 and 6 andwelded therebetween so as to form a rigid interconnection of pairs oflegs 3 to pairs of legs 6. The longitudinally extending stringers areconveniently angle bars one web of each of which is vertically disposedto form a support surface for a transversely extending shaft 16,rotatably journaled in appropriate bearings 17 and 18 boltedrespectively to longitudinally extending stringers 13 and 14.

The discharge standard formed by vertical legs 8 and cross beam 9 isconnected to the intermediate standard 6-7 by longitudinally extendingangle bars 21 and 22, the angle bars being used to support variousstructures as will hereinafter be explained. Also connecting theintermediate standard 6-7 with the discharge standard 8-9 is alongitudinally extending guide rail 23 (FIG. 2) providing opposed flatsurfaces 24 and 26 forming guide and support surfaces upon whichassociated structure may move longitudinally of the rail. Suchassociated structure, as will hereinafter be explained, is alsosupported adjacent the opposite side of the main frame on alongitudinally extending slide shaft 24, opposite ends of which aresupported in appropriate bearings 26 and 27, the bearing 26 being fixedto one of the legs 6 and the bearing 27 being fixed as indicated in FIG.1 to the cross beam 9.

Supported on the guide bar 23 and slide shaft 24 is an auxiliarycarriage frame designated generally by the numeral 29. The auxiliarycarriage is provided with transversely extending beams 31 and 32, bothbeams at corresponding ends adjacent the guide bar 23 being providedwith a roller bearing assembly designated generally by the numeral 33and including a bracket 34 on which rollers 36 and 37 are rotatablyjournaled as shown. Referring to FIG. 2, it will be seen that roller 36on each beam is adapted to roll along the upper surface 24 of the guiderail 23, while the roller 37 is adapted to roll along the surface 26 ofthe guide rail 23. At their other ends, the beams 31 and 32 terminate inappropriate sleeve type bearings 38 and 39 slidably journaled on theslide shaft 24. It will thus be seen that by virtue of the slidableengagement of the bearings 38-39 on slide shaft 24 and the rollingcontact between rollers 36-37 and the guide rail 23, the auxiliarycarriage is permitted to move longitudinally of the main frame withinpredetermined limits as will hereinafter be explained.

The auxiliary carriage also includes a housing portion formed bydepending side walls 41 and 42, preferably generally U-shaped asindicated in FIG. 1, the lower ends of the U-shaped side walls beingconnected by a bottom wall 43 as shown in FIG. 2. Mounted within thehousing formed by walls 41-43 are a plurality of pairs of guide rollers46-47, the roller 47 of each pair being provided with a suitable surfaceconfiguration such as recess 48 to accommodate the configuration of thestrip material being run through the cutoff mechanism. The opposingroller 46 of that pair is either provided with a smooth exteriorperiphery or is provided with a recess complementary to a projectingportion of the configuration being run. It should of course beunderstood that these rollers may be removed and others of differentconfiguration substituted therefor.

As viewed in FIGS. 1 and 2, there are four such pairs of rollerssupported within the auxiliary carriage housing. Rollers 46 of each pairare journaled for free rotation on shafts 49, while opposing rollers 47of each pair are journaled for free rotation on shaft 51. As shown inFIG. 2, shafts 49 and 51 are appropriately supported at each end onbearings 52 fixed to side walls 41 and 42.

Supported on the transversely extending beam 31 (FIG. 2), and forming apart thereof, is a vertically extending journal plate 56 in the natureof a gusset, one end 57 of which supports a bearing assembly designatedgenerally by the numeral 58 (FIG. 7) and including an outer housing 59equipped with an outer bearing race 61 cooperating with an inner bearingrace 62 press fitted on the outside periphery of a slide bearing sleeve63 appropriately keyed for longitudinal sliding movement along arotatable shaft 64. The shaft 64 extends longitudinally of the mainsupport frame, being positioned slightly above slide shaft 24 asindicated in FIG. 2. To lend further support to the slide bearing sleeve63, the outer end portion 57 of the plate 56 is apertured coaxial to theshaft 67 and is provided with a bearing assembly designated generally bythe numeral 66 and including inner and outer races as shown. From theforegoing, it will be apparent that as the auxiliary frame moveslongitudinally along the guide bar 23 and slide shaft 24, the journalplate 56 moves with the auxiliary carriage while being slidablysupported as previously described.

The midsection of the vertically extending journal plate 56 is aperturedas shown in FIG. 1 and is provided with a bearing support sleeve 66press fitted in the opening. The opening in the journal plate 56coaxially accommodates a shaft 67, preferably splined for reasons whichwill hereinafter appear, and on which shaft is slidably disposed a hub68. Since it is not desirable that the hub rotate in relation to shaft67, the hub preferably includes splines complementary to the splines ofshaft 67. The hub is rotatably disposed coaxially within the bearingsleeve 66, and is supported in this position by an appropriate bearingassembly 69.

The hub 68 also supports a bearing assembly 71 disposed intermediate theends of the hub, and hearing assembly 72 press fitted on the oppositeend of the hub from bearing assembly 69. Between bearing assemblies 71and 72 there is provided a sheave or pulley 73 adapted to receive aflexible, drive belt 74 as shown in FIG. 1. With respect to bearingassembly 71, there is mounted for rotation with the outer race of thisbearing assembly a mounting bracket 76, preferably annular inconfiguration and having attached to its outer periphery a largediameter sprocket 77 for reception of a roller chain 78.

It will thus be seen that since the hub 68 is splined to shaft 67,rotation of the shaft effects rotation of the hub in relation to thebracket 76 and sprocket 77. On the other hand, since the bracket 76 andsprocket 77 are attached to the outer race of the bearing assembly 71,this assembly may be rotated about the axis of shaft 67 without rotationof the shaft.

Rotatably mounted on the bearing assembly 72 for rotation in relation tothe shaft 67 is a journal sleeve 81 on one end of which is secured as bywelding a mounting plate 82 having an aperture 83 therein concentricallydisposed about the hub 68, and having its adjacent peripheral portionwelded to one end of the sleeve 81. As seen in FIGS. 1 and 2, the plate82 extends away from the bearing sleeve 81 in the nature of a cantileverarm and on its free end portion 84 is provided with an aperture 86within which is mounted a bearing assembly 87.

As seen in FIG. 1, a similar support plate 88 lies parallel to andspaced behind plate 82, and plate 88 is also provided with an aperture89 axially aligned with the aperture 86 and also utilized to support abearing assembly 91. Suitably mounted in the two bearing assemblies 87and 91 is a mandrel 92 carrying a saw blade 93 on one end thereof and asheave or pulley 94 keyed to the mandrel and disposed between plate 82and 88. Drive belt 74 connects pulley 73 and pulley 94 to effectcontinuous rotation of saw blade 93.

As indicated above, since pulley 73 carrying drive belt 74 is keyed tohub 68, and since the hub is in turn splined to shaft 67, rotation ofshaft 67 will necessarily result in rotation of pulleys 73 and 94 andconsequently, the saw blade 93. To effect rotation of shaft 67, theshaft at one end is journaled for rotation in a bearing 96 supported onthe standard 8-9, while at its other end the shaft is journaled in abearing assembly 97 detachably secured to the intermediate standard 6-8.The end of the shaft associated with the bearing 97 is provided with areduced-in-diameter section 98 engaged by a coupling member 99 which isalso adapted to engage the shaft 101 of a drive motor 102.

The drive motor is conveniently a 1 HP double-shaft type with the secondshaft 103 projecting from the opposite end of the motor housing andsupporting a pulley 104 adapted to carry a gear belt 106 for thetransmission of power between the motor 102 and a second pulley 107mounted on the shaft 108 of a power unit 109 equipped with a powertakeoff shaft 112 engaging a coupling 113, the other end of whichengages the reduced-in-diameter portion 1 14 on the associated end ofshaft 64. As previously noted, shaft 64 carries hub 63, carrying thebearing assembly 58 associated with the longitudinally movable auxiliarycarriage 29. Also mounted on hub 63 as by press fitting thereon, is asprocket 116 connected by roller chain 78 previously discussed tosprocket 116 connected by roller chain 78 previously discussed tosprocket 77 journaled on the hub 68. Slack in the chain 78 is taken upby an idler sprocket 117 as shown best in FIG. 2.

It will thus be seen that when the electric motor 102 is energized,shaft 67 is caused to rotate, thus rotating hub 68. Rotation of hub 68,of course, results in driving pulley 73, thus causing rotation of sawblade 93 which rotates continuously at constant speed so long as motor102 is energized.

Energization of motor 102 also causes rotation of drive belt 106,effecting rotation of shaft 108 in the power unit 109. This power unitis conveniently a Warner Electropak sold as Model No. EP-SOO andincludes clutch and brake means actuated and controlled in a mannerwhich will hereinafter be explained. It should be noted that with shaft108 the power unit 109 rotating, shaft 64, axially aligned with thedrive shaft of the power unit, does not rotate unless the brakeincorporated in the power unit is released and the clutch engaged so asto complete a power path through the power unit. When that occurs, thepower unit causes rotation of shaft 64 and hub 63 splined thereto.

Since sprocket 116 is press fitted or keyed to hub 63, this sprocketwill be caused to rotate with shaft 64, thus effecting rotation ofsprocket 77, causing the bearing bracket 76, bearing sleeve 81, andattached support plates 82 and 88 carrying mandrel 92 to swing in an arearound the axis of the shaft 67 on which they are mounted. It will thusbe seen that continuous rotation of the saw blade 93 continues atwhatever speed is provided by the drive ratios between the motor andmandrel 92, while the entire saw unit carried on the cantilever arm 84will be caused to rotate in an are about the axis of shaft 67.

As viewed in FIG. 2, swinging movement of the rotating saw blade in anare about the shaft 67 will carry it in an orbital path which extendsthrough any elongated material carried on the rollers 47 of theauxiliary carriage 29. The manner and means for controlling suchmovement of the saw blade in an are about the shaft 67 will be explainedin greater detail hereinafter in conjunction with FIGS. 1, 2, 5 and 7.

To effect longitudinal displacement of the auxiliary carriage 29 inrelation to the main support frame, and specifically longitudinally ofthe support and guide bar 23 and slide shaft 24, the auxiliary carriageis provided with a laterally extending bracket 121, the free end 122 ofwhich is detachably bolted to an anchor bracket 123 anchored by anysuitable means to a roller chain 124. The roller chain is carried by asprocket 126 normally adapted to rotate freely on the shaft 16, andbeing provided with an elongated hub 127 which connects the sprocket 126to a magnetically operated clutch mechanism 128, including the hub 127,and provided also with a drive sleeve 129 arranged coaxially about thehub 127 and on which are fixedly mounted a pair of sprockets 131 and132.

The sprocket 131 is connected by a roller chain 133 to relativelysmaller sprocket 134 keyed to the end portion 136 of a shaft 137journaled adjacent the discharge end 138 of a pair of elongatedstringers formed by angle bars and which form a part of a conveyor todeliver elongated material to the cutoff mechanism. The shaft 137 alsosupports, outboard of one of the elongated stringers 138 and keyed tothe stub shaft 136 of the shaft, a sprocket 139 connected by a rollerchain 141 to a sprocket 142, keyed to shaft 143 together with companionsprocket 144, as shown. Shaft 143 is journaled on the stringers 138 at apoint spaced from shaft 137 as illustrated in FIG. 1.

The sprocket 144 is connected by an appropriate roller chain 146 with adrive sprocket (not shown) connected to one of the drive pulleys 147 ofthe apparatus in which the elongated material is being formed and fromwhich it is being discharged at constant rate. It will thus be seen thatregardless of the speed of the discharge pulley 147 of the formingapparatus, chain 146 drives shafts 143 and 137 at a proportionate rateso that the material to be cut passes into the cutting mechanism at thesame rate as it emerges from the forming apparatus. To insure suchcontinued movement of the material to be cut, shafts 137 and 143 areprovided with appropriate pairs of drive rollers 148 and 149. Thesedrive rollers are generally in line with and complement rollers 47carried in the auxiliary carriage 29.

It will thus be seen that since sprocket 134 is mounted on the same stubshaft 136 on which sprocket 139 is mounted, rotation of sprocket 139effects rotation of sprocket 134, which by virtue of its connection withsprocket 131 by roller chain 133, effects rotation of the control sleeve129 on hub 127. Normally, such rotation of the control sleeve is freeand at a rate proportional to the rate at which the feed rollers 148 and149 are rotated. At selected times, however, when it is desired that thecutoff blade be energized and the auxiliary carriage move longitudinallyof the main frame to effect a cutoff operation, the magneticallyoperated travel clutch 128 is energized by appropriate control means tobe described hereinafter, so that an instantaneous and releasableinterconnection is formed between the sprocket 132 and sprocket 126.

This results in sprocket 126 being rotated at the same rate as driverollers 148-149-4647 and, since the roller chain 124 driving sprocket126 is fastened through anchor bracket 123 to the auxiliary carriage 29,it will be seen that the auxiliary carriage moves longitudinally of themain frame at the same rate at which the roller chain 124 is driven bythe sprocket 126. Thus, when the power unit 109 is activated so as todrive the cantilever saw arm 84 in an arc about the shaft 67, the sawblade moves longitudinally of the main frame at the same rate as theauxiliary carriage 29. There is, therefore, no tendency for the sawblade to bind in the material through which it is passing, inasmuch asthe saw blade and material being out are moving longitudinally throughthe frame at the same rate.

The point at which cutoff is to occur is determined by energization andde-energization of a pair of clutches and one or more brake units whichinitiate movement of the auxiliary frame 29 on which the saw blade 93 ismounted for movement at the same speed as the material to be cut, andthereafter energization of the saw to swing the saw blade so as to cutthrough the material at the correct length. These functions areperformed by the four circuits generally designated as cutoff sawcontrol circuits 159 illustrated in FIG. 8.

The cutoff control circuitry includes a two-dial pulseoperated switchingunit for alternately controlling a brake and clutch in thecontrol unit128 in conjunction with operation of the apparatus. Such a switchingunit may be purchased commercially from Warner Electric Brake and ClutchCompany, Beloit, Wisconsin, under the trade designation MCS-l 17. Alsoincluded in the cutoff saw control circuitry is a clutch-brake controlunit including a photoelectric relay sold commercially by FarmerElectric Products Co., Inc., Natick, Massachusetts, under the tradedesignation TR- 4, this unit producing a one-shot relay operationoperating with a power supply equipped to provide a single torquecontrol dial to effect control of a clutch mechanism for purposes whichwill hereinafter be explained. A power supply found to be satisfactoryis sold commercially by Warner Electric Brake and Clutch Co. under thetrade designation MCS- Other equivalent power supplies may, of course,be used.

Referring to FIGS. and 6, it will there be seen that a light-sensitivephotoelectric cell 151 is positioned to receive a light beam 152emanating from a light source 153. The light source and light sensitivecell are mounted on opposite sides of a discharge conveyor 154 alongwhich a length 156 of the material to be cut is caused to move by thedrive rollers 47. It is the function of the photoelectric cell and lightsource to sense the end of a strip of material to be out after it hasemanated from the forming apparatus a predetermined length. To

control the length, the photoelectric cell assembly 151-153 may be movednearer or farther from the cutoff saw. Interruption of the beam by theend of the strip material initiates movement of the auxiliary frame 29on which the saw blade is mounted at the same speed as the material tobe cut.

Energization of the saw to swing the saw blade so as to cut the materialat the correct length is controlled by the circuitry illustrated in FIG.7. When the light beam is interrupted, the TRB-4 relay previouslyidentified as available commercially from Farmer Electric Products Co.,Inc. under the trade designation TR-4 is actuated, thus closing contacts157 to complete a circuit through and energize a travel clutch containedin the power unit 128 illustrated in FIG. 2. As previously explained,energization of this travel clutch or power unit 128 initiates rotationof sprocket 126 and therethrough roller chain 124 attached to theauxiliary carriage 29. The auxiliary carriage is thus caused to movelongitudinally of the frame at the same rate of movement as the materialto be cut.

As soon as the auxiliary carriage starts moving, normally open-camoperated switch 158, preferably supported at some convenient point onthe frame, such as guide bar 23, where any movement of the auxiliarycarriage causes the normally open switch to be closed, results inenergization of the Warner saw head clutch contained in power unit 109,thus causing shaft 64 to rotate rapidly by virtue of its connectionthrough belt 106 to the electric motor 102. Energization of the Warnersaw head clutch unit is in most instances momentary, resulting perhapsin no more than one complete revolution of the cantilever saw bladesupport arm about the shaft 67. It will be remembered that sprocket 77mounted on shaft 67 is connected by roller chain 78 to sprocket 116splined to shaft 64.

Thus, the only time that sprocket 77 rotates is when shaft 64 is causedto rotate momentarily by energization of the Warner head clutchassembly. Before the saw blade support arm 84 has made one completeorbital swing about shaft 67, the saw head switch 159, preferably acam-operated unit, is mechanically actuated by the support arm 84 toswitch the electronic circuitry of the Warner controls so that thesaw-control clutch is disengaged and a saw head brake (not shown) issimultaneously imposed to thus bring the saw head to an abrupt stop.

The saw head switch is preferably positioned at an appropriate point onthe frame so that as the saw head support arm orbits about shaft 67 itmechanically trips the switch into its closed position. Actuation of thesaw head switch also turns to off condition the latch to the TRBphotocontrol relay and energizes this relay. As soon as the photocontrolrelay is deenergized, the

travel clutch contained in power unit 128 is also deenergized and aheavy coil spring 161 (FIG. 2) returns the auxiliary carriage carryingthe saw blade to its original position. The frame switch 158 iscam-actuated during this return motion, but there is no responsivereaction by the saw head clutch because the TRB relay contacts 1-3 (FIG.8) are open. Safety switch 162 is provided in the TRB relay circuit toautomatically return the auxiliary frame to its initial position if amalfunction occurs in the head switch or if the saw motor is notworking.

From the foregoing, it will be seen that close and accurate control ofmovement of the auxiliary carriage 29 and the saw head carried therebyis effected through the control mechanisms provided. It will also beunderstood that many different widths of material passing through thecutoff mechanism may be effectively cut by the saw, the only limitationbeing the maximum chord subtended by the orbital arc made by the saw asit moves around the shaft 67 as an axis of rotation. Obviously, theeffective chord of this arc may be varied by increasing the diameter ofthe saw blade 93 and/or increasing the length of the support plates 82and 88 so as to lengthen the orbital arm carrying the saw blade.

While the specification has been described in connection with the cutofffunction being performed on elongated strip material, it should beunderstood that many other type materials may be cut through utilizationof this mechanism.

Having thus described my invention, what is claimed to be novel andsought to be protected by letters patent is as follows:

1. An automatic cutoff mechanism for cutting without interruptionelongated strip material to predetermined lengths while said elongatedstrip material moves in the direction of its length at a predeterminedrate, comprising:

a. a main support frame including a conveyor means for supporting andguiding said elongated strip material prior to its being cut;

b. auxiliary carriage means mounted on the main frame and selectivelymovable thereon at a rate equal to the rate of movement of said stripmaterial through said main frame;

c. cutoff means mounted on said auxiliary carriage means and movabletherewith in relation to said main frame at the same rate as said stripmaterial, said cutoff means including a cantilever arm pivoted at oneend on said auxiliary carriage and having a cutoff blade rotatablymounted on its free end for selective orbital movement in relation tosaid auxiliary carriage, said cutoff blade being adapted to cut throughsaid strip material during a portion of its orbital movement;

d. control means operatively associated with said auxiliary carriagemeans and cutoff means and correlated to movement of a predeterminedlength; and,

e. said main frame further including a power generating section and apower utilization section, electric motor means supported in said powergenerating section, selectively engaging power transfer means supportedin said power generating section and connected with said electric motormeans, said power transfer means including a selectively engaging anddisengaging clutch for transmitting or interrupting transmission ofpower by said power transfer means, continuously rotatable shaft meanscoupled to said electric motor means and extending into said powerutilization section of said main frame, selectively rotatable shaftmeans coupled to said power transfer means and rotatable when the clutchtherein is engaged, said shaft extending into said power utilizationsection, means connecting said continuously rotatable shaft to saidcutoff blade to effect continuous rotation thereof, and means connectingsaid selectively rotatable shaft to said cantilever arm of the cutoffmeans to effect selective orbital movement thereof.

2. The combination according to claim 1, in which orbital movement ofsaid cantilever arm is initiated when said means for sensing the forwardedge of the moving strip to be cut is activated thereby.

1. An automatic cutoff mechanism for cutting without interruption elongated strip material to predetermined lengths while said elongated strip material moves in the direction of its length at a predetermined rate, comprising: a. a main support frame including a conveyor means for supporting and guiding said elongated strip material prior to its being cut; b. auxiliary carriage means mounted on the main frame and selectively movable thereon at a rate equal to the rate of movement of said strip material through said main frame; c. cutoff means mounted on said auxiliary carriage means and movable therewith in relation to said main frame at the same rate as said strip material, said cutoff means including a cantilever arm pivoted at one end on said auxiliary carriage and having a cutoff blade rotatably mounted on its free end for selective orbital movement in relation to said auxiliary carriage, said cutoff blade being adapted to cut through said strip material during a portion of its orbital movement; d. control means operatively associated with said auxiliary carriage means and cutoff means and correlated to movement of a predetermined length; and, e. said main frame further including a power generating section and a power utilization section, electric motor means supported in said power generating section, selectively engaging power transfer means supported in said power generating section and connected with said electric motor means, said power transfer means including a selectively engaging and disengaging clutch for transmitting or interrupting transmission of power by said power transfer means, continuously rotatable shaft means coupled to said electric motor means and extending into said power utilization section of said main frame, selectively rotatable shaft means coupled to said power transfer means and rotatable when the clutch therein is engaged, said shaft extending into said power utilization section, means connecting said continuously rotatable shaft to said cutoff blade to effect continuous rotation thereof, and means connecting said selectively rotatable shaft to said cantilever arm of the cutoff means to effect selective orbital movement thereof.
 2. The combination according to claim 1, in which orbital movement of said cantilever arm is initiated when said means for sensing the forward edge of the moving strip to be cut is activated thereby. 